Timed input-output motion transmitting device

ABSTRACT

A motion transmitting mechanism having a predetermined delay between input and output motion. Movement of the input is transmitted through a lost motion device, such as a spring, to an input piston. Movement of the input piston causes the displacement of a fluid medium which flows at a controlled rate through a restriction. Movement of the input piston is transmitted to an output piston through a lost motion device. Movement of the output piston causes the displacement of the fluid medium at a controlled rate through the restriction. The output moves simultaneously with the output piston.

Need

[4 1 Apr. 17, 1973 TIMED INPUT-OUTPUT MOTION TRANSMITTING DEVICE [75]Inventor: Lester E. Need, Brownsburg, Ind.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Dec. 8, 1971 [21] Appl. No.: 205,845

[52] US. Cl ..74/470, 74/865 [51] Int. Cl. ..G05g l/00 [58] Field ofSearch ..74/470, 1 10 [56] References Cited UNITED STATES PATENTS2,647,412 8/1953 Warmoes et a1 ..74/47O 2,688,884 9/1954 Warmoes et a]..74/470 Primary ExaminerMilton Kaufman Att0rney--W. E. Finken et al.

[57] ABSTRACT A motion transmitting mechanism having a predetermineddelay between input and output motion. Movement of the input istransmitted through a lost motion device, such as a spring, to an inputpiston. Movement of the input piston causes the displacement of a fluidmedium which flows at a controlled rate through a restriction. Movementof the input piston is transmitted to an output piston through a lostmotion device. Movement of the output piston causes the displacement ofthe fluid medium at a controlled rate through the restriction. Theoutput moves simultaneously with the output piston.

3 Claims, 2 Drawing Figures TIMED INPUT-OUTPUT MOTION TRANSMITTINGDEVICE The invention herein described was made in the course of workunder a contract or subcontract thereunder with the Department ofDefense.

This invention relates to motion devices and more particularly to motiontransmitting devices wherein there is a predetermined delay betweeninput motion and output motion.

In many linkage systems it is desirable to provide a predetermined delaybetween input movement and output movement of a linkage. This isparticularly true in the throttle linkage connection between an engineand a transmission wherein the engine is a diesel type or compressionignition engine and the transmission is a hydromechanical type. Theobject of the throttle connection is to impose an engine torque demandsignal on the transmission control. It is desirable to have the torquedemand signal follow the actual engine torque output closely. In dieselengines the actual engine torque development lags behind engine throttlemovement. It is, therefore, desirable to locate a motion transmittingmechanism having a predetermined delay between input and output motioninto the throttle linkage to compensate for the lag time.

The present invention provides a predetermined delay between input andoutput motion by locating lost motion mechanisms and fluid displacingmechanisms between the input and output members. The input memberoperates on a piston through a spring so that a force on the inputmember causes the piston to generate a static pressure in an enclosedfluid medium. The static pressure developed by the force on the pistonis relieved by fluid flow through a restriction in a second piston thuspermitting the first piston to move. Movement of the first pistonimposes a force on the second piston through a spring connectiontherebetween which force on the second piston generates a staticpressure in the fluid medium. The static pressure thus generated isrelieved by fluid flow through the restriction in the second piston andpermits movement of the second piston. The output member is connected tothe second piston and moves therewith. Thus the relative movement of theinput and output members is controlled by the spring members and thefluid displacement of the pistons.

It is an object of this invention to provide an improved motiontransmitting mechanism having a time delay between input and outputmotion controlled by lost motion mechanisms and fluid displacement.

It is another object of this invention to provide in an improved motiontransmitting mechanism an input member which is drivingly connectedthrough a spring to a fluid displacing member which responds to a forceon the input member to displace fluid at a predetermined rate throughthe control restriction in a second fluid displacing member andsimultaneously imposes a spring force on the second fluid displacingmember such that the second fluid displacing member will displace fluidat a controlled rate through the restriction after the first fluiddisplacing member has come to rest.

It is another object of this invention to provide in an improved motiontransmitting mechanism, an input member and an output member operativelyconnected by a plurality of lost motion mechanism and fluid displacingmeans whereby the lost motion mechanisms of the fluid displacing meanscooperate to provide a controlled rate of fluid flow to establish apredetermined time delay by the movement of the input and outputmembers.

These and other objects and advantages of the present invention will bemore apparent from the following description and drawings in which:

FIG. 1 is a cross-sectional elevational view of the invention; and

FIG. 2 is a graph showing the time relationship between input and outputmovement.

Referring to the drawings there is shown in FIG. 1 a housing generallydesignated 10 having a body portion 12, a cover 14 and an end cap 16.The cover 14 is secured by a plurality of threaded fasteners 18 to thebody 12 and the end cap 16 which is bonded to or otherwise secured tothe body 12. The body 12, cover 14 and end cap 16 cooperate to form areservoir 20.

The body 12 has a bore 22 which is closed at one end by the cap 16. Acup shaped piston 24 is slidably disposed in the bore 22. A pair ofspring seats 26 and 28 are located in the piston 24 by a pair of snaprings 30 and 32 respectively which spring seats have compressedtherebetween a spring 34. Another spring 36 also abuts the spring seat26 and is held in compression by a snap ring 38 which abuts the springseat 26 and an expanded head 40 formed on an input rod 42. The input rod42 has a groove 44 which locates the snap ring 38. The input rod 42 isslidably disposed in a bushing 46 located in the end cap 16 and has anend portion 48 secured thereto.

The snap ring 32 also locates a spring seat 50 which cooperates withanother spring seat 52 located in the piston 24 by a snap ring 54. Thespring seats 50 and 52 cooperate to maintain a compression spring 56 incompression therebetween. The spring seat 52 abuts a piston 58 formed onone end of an output rod 60. The piston 58 is slidably disposed in abore 62 formed in the piston 24 and has a flow restriction 64 thereinwhich permits controlled fluid flow from one end of bore 22 to theother. Also abutting the piston 58 is another spring seat 66 which islocated in the piston 24 by a snap ring 68. A compression spring 70 isheld in compression between the springseat 66 and the end of piston 24.The output rod 60 is slidably disposed in a bushing 72 located in thebody 12 and has secured thereto an end portion 74 opposite the piston58.

In the position shown a fluid cavity 76 is formed in the bore 22 betweenthe piston 24 and the end cap 16 and is in fluid communication with thereservoir 20 through a passage 78. When the piston 24 abuts or isclosely adjacent to the end cap 16 a chamber 80 formed in the bore 22between the piston 24 and the body 12 is in fluid communication with thereservoir 20 through a passage 82. Fluid flow from the chambers 76 and80 past the input rod 42 and output rod 60 is prevented by seals 84 and86 respectively which are located in the end cap 16 and body 12respectively.

During operation the input rod 42 is moved to the right therebycompressing the spring 36 between the.

spring seat 26 and the expanded head 40 of the input rod 42. This forcein the spring 36 is transmitted to the piston 24 through the snap ring30 so that the piston 24 acts on the fluid medium .in the chamber 76 tocreate a static pressure therein. The static pressure in the chamber 76is relieved by fluid flow through a plurality of openings 88 in thespring seat 26 and through the control restriction 64. Fluid flowthrough the restriction 64 occurs at a controlled rate thus controllingthe movement of the piston 24. As the piston 24 moves to the right thespring 70 is compressed between the end of piston 24 and the spring seat66 which transmits a force to the piston 58. Also as the piston 24 movesthe passage 78 is closed. The force in spring 70 is less than the forcein spring 36 and is therefore not sufficient to overcome the pressuregenerated in chamber 76 while the piston 24 is moving since the pressurein chamber 76 is proportional to the force in the spring 36. The piston24 will however reach a stabilized position wherein the spring 36 istrapped in compression between the expanded head 40 and the snap ring 38and, therefore, no longer imposes a force on the piston 24. At this timethe piston 58 will be moved by the force in spring 70. However, themovement of piston 58 must result in the displacement of fluid from oneside of the piston 58 to the other, therefore, the restriction 64 againcontrols fluid flow and the time rate at which the piston 58 moves.Since the output rod 60 is secured to the piston 58 the output rod movesat the same time as the piston 58 does. Assuming that the mechanism hasbeen moved from the position shown either to a position with the piston24 adjacent the end cap 16 or to an intermediate position, the input rod42 can then be moved to the left. Movement of the input rod in thisdirection will cause the spring 34 to be further compressed between thespring seats 26 and 28 thus transmitting a spring force to the piston 24through the spring seat 28 and snap ring 32. This force will result in astatic pressure in chamber 80 which pressure is relieved by fluid flowat a control rate through the restriction 64 thus permitting movement ofthe piston 24. Movement of the piston 24 causes the spring 56 to befurther compressed between the spring seats 50 and 52 thus imposing aforce on the output piston 58. The force in spring 34 is greater thanthe force in spring 36, therefore, the static pressure acting on theleft side of piston 58 will prevent movement thereof since the staticpressure is proportional to the force in spring 34. The piston 24 will,however, move to a point of stability wherein the spring 34 reaches itstrapped position shown at which time the spring 56 will begin movementof the piston 58 which will result in controlled flow of fluid throughthe restriction 64 to control the movement of the output rod 60.

From the above description it is obvious that the movement of the outputmember lags behind the movement of the input member at a predeterminedrate. This time delay is shown graphically in FIG. 2 which shows thatthe input 42 is moved from a minimum position to a maximum position orfrom intermediate position. Movement of the input member 42 is followedby movement of the piston 24 at a time rate controlled by fluid flowthrough the restriction 64. When the piston 24 has reached a point ofstability the output 60 and piston 58 will move at a controlled rateagain determined by fluid flow through the restriction 64.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What IS claimed is:

1. A motion transmitting mechanism comprising, a movable input member; amovable output member; first fluid displacing means; spring meansbetween said input member and said first fluid displacing means forpermitting lost motion therebetween; second fluid displacing meanssecured to said output member and having restriction means therein; andsecond spring means for permitting lost motion between said first andsecond fluid displacing means; said restriction means initiallyproviding a time control for the fluid displaced by said first fluiddisplacing means and secondly providing a time control for the fluiddisplaced by said second fluid displacing means and cooperating withsaid first and second spring means to provide a time delay betweenmovement of said input and output members.

2. A motion transmitting mechanism comprising, a movable input member; amovable output member; first fluid displacing piston means; spring meansbetween said input member and said first fluid displacing piston meansfor permitting lost motion and for transmitting a force therebetween;second fluid displacing piston means secured to said output member andhaving restriction means therein; and second spring means for permittinglost motion and for transmitting a force between said first and secondfluid displacing means; said restriction means initially providing atime control for the fluid displaced by said first fluid displacingpiston means and secondly providing a time control for the fluiddisplaced by said second fluid displacing piston means and cooperatingwith said first and second spring means to provide a time delay betweenmovement of said input and output members.

3. A motion transmitting mechanism comprising, an input member; anoutput member; housingmeans having a bore therein; first piston meansslidably disposed in said bore; first spring means operatively connectedbetween said input member and said first piston means for transmittingforces while permitting relative movement therebetween; second pistonmeans secured to said output member and being slidably disposed in saidfirst piston means; second spring means operatively connected betweensaid first and second piston means for transmitting forces therebetween;a fluid filling said bore and said first piston means; and restrictionmeans in said second piston means for initially controlling fluid flowin response to a force transmitted from said input member to said firstpiston means, and secondly controlling fluid flow in response to a forcetransmitted from said first piston means to said second piston means.

1. A motion transmitting mechanism comprising, a movable input member; amovable output member; first fluid displacing means; spring meansbetween said input member and said first fluid displacing means forpermitting lost motion therebetween; second fluid displacing meanssecured to said output member and having restriction means therein; andsecond spring means for permitting lost motion between said first andsecond fluid displacing means; said restriction means initiallyproviding a time control for the fluid displaced by said first fluiddisplacing means and secondly providing a time control for the fluiddisplaced by said second fluid displacing means and cooperating withsaid first and second spring means to provide a time delay betweenmovement of said input and output members.
 2. A motion transmittingmechanism comprising, a movable input member; a movable output member;first fluid displacing piston means; spring means between said inputmember and said first fluid displacing piston means for permitting lostmotion and for transmitting a force therebetween; second fluiddisplacing piston means secured to said output member and havingrestriction means therein; and second spring means for permitting lostmotion and for transmitting a force between said first and second fluiddisplacing means; said restriction means initially providing a timecontrol for the fluid displaced by said first fluid displacing pistonmeans and secondly providing a time control for the fluid displaced bysaid second fluid displacing piston means and cooperating with saidfirst and second spring means to provide a time delay between movementof said input and output members.
 3. A motion transmitting mechanismcomprising, an input member; an output member; housing means having abore therein; first piston means slidably disposed in said bore; firstspring means operatively connected between said input member and saidfirst piston means for transmitting forces while permitting relativemovement therebetween; second piston means secured to said output memberand being slidably disposed in said first piston means; second springmeans operatively connected between said first and second piston meansfor transmitting forces therebetween; a fluid filling said bore and saidfirst piston means; and restriction means in said second piston meansfor initially controlling fluid flow in response to a force transmittedfrom said input member to said first piston means, and secondlycontrolling fluid flow in response to a force transmitted from saidfirst piston means to said second piston means.